This invention relates to production of poly(ester/carbonates) from bisphenol A ("BPA") and terephthalic acid ("TPA") using essentially only pyridine as the reaction medium.
It has been proposed in U.S. Pat. No. 3,030,331 of Apr. 17, 1962 and 3,169,121 of Feb. 9, 1965 both to E. P. Goldberg to produce poly(ester/carbonates) by adding phosgene to a pyridine solution of bisphenol A and terephthalic acid. It has been found however, that at least when the ratio of bisphenol A:terephthalic acid is in the range between about 2.0:0.8 and 2.0:1.3, the conditions of Goldberg's examples result in polymers which are deficient in terephthalic ester moiety and which are hazy or opaque and have low strength and toughness (U.S. application Ser. No. 764,623 of Prevorsek et al. filed Feb. 1, 1977; published as West German DOS 2,714,544 of Oct. 2, 1977). Such defects are confirmed in Table 1 below, by the results obtained at temperature of 30.degree. C. (Goldberg's temperature condition.)